Cycle 1 (2011 Deadline)
Assessment of the tropospheric HONO budget: instrumental development and field measurments
PI: Charbel Afif, Université Saint Joseph de Beyrouth
U.S. Partner: Sebastian Dusanter, University of Indiana
Project Dates: May 2012 - May 2014
Climate change is one of the most important environmental concerns of the 21st century, and there are concerns regarding atmospheric warming due to increases of greenhouse gas emissions. Reliable climate projections will depend on how well models of atmospheric chemistry can forecast concentrations of greenhouse gases, whose lifetimes depend on the global concentration of the hydroxyl (OH) radical. However, there are still large uncertainties related to the atmospheric OH budget. Recent studies focusing on the chemistry of nitrous acid (HONO), an important source of the OH radical, indicate that model-predicted concentrations of HONO do not agree with field measurements performed in various environments (urban, rural, forests, etc.). These results suggest that our understanding of HONO chemistry is incomplete and call into question our ability to model the atmospheric oxidative capacity and therefore our ability to predict future changes in the atmosphere.
The project will support construction of a reliable instrument (NitroMAC) at the Université Saint Joseph de Beyrouth to measure atmospheric HONO concentrations. The principal investigator will work to develop a calibration source of HONO and compare data collected by his new NitroMAC instrument with those gathered by his U.S. partner’s HONO instrument. NitroMAC will be deployed by the collaborating researchers during intensive field campaigns in both the United States and Lebanon, with the US partner to provide the infrastructure for field measurements and part of the equipment necessary for the intercomparison experiment. Collaborations through the field campaign measurements and subsequent data interpretation will promote the sharing of knowledge between the researchers involved. The research outcomes of the project should also benefit the atmospheric science community by adding more constraints to the HONO budget and by improving understanding of the oxidative capacity of the atmosphere. Furthermore, the project will initiate air quality studies in Lebanon and will help promote the development of efficient strategies for pollution control.
Summary of Recent Activities
Beginning July 27, 2013, the PI Dr. Charbel Afif participated in a four-week field campaign in Indiana with his U.S. co-partner, Prof. Philip Stevens. The instruments needed for the field campaign had been shipped from Beirut to Bloomington during the first week of July. The field campaign encountered some difficulties due to late delivery of some of the reagents and supplies that had been ordered, but the overall results are promising. Data will be analyzed after the shipment of Dr. Afif’s NitroMAC instrument and its calibration source, NitroCal, back to his university. Journalists from Indiana University interviewed Prof. Stevens and Dr. Afif during the field campaign, but their article on the project has not yet been published. After returning to Lebanon, Dr. Afif posted a new vacancy for a postdoctoral researcher to continue the data treatment and analysis of the summer field campaign. He is also launching the procurement process to acquire air quality analyzers and prepare for the planned field campaign in Beirut.
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